Dual Quad Carburetor Set Up
HTML-код
- Опубликовано: 5 сен 2024
- Setting up and tuning dual quad carburetors isn't easy. Its harder when you don't have the tools or the process to make it happen. Join along for a few ideas on how to make it an easier time. These tips apply to any low rise or tunnel ram set up, though we'll use this Edelbrock kit as demonstration.
AFR kit - amzn.to/3kzcBJ1
Carb install parts
Wood laminate spacer - amzn.to/2JOtoKm
Phenolic spacer - amzn.to/2JMBPpo
Mr Gasket base gasket - amzn.to/2LjIUi1
Pressure regulator - amzn.to/3lJo2NB
Cheaper pressure regulator - amzn.to/3glXxNi
Edelbrock fuel line kit with filter - amzn.to/2JD5vFL
Edelbrock fuel line kit w/o filter - amzn.to/2JRNweB
10 micro filter - amzn.to/2JLx53j
100 micron filter - amzn.to/36LwiIJ
Liquid filled gauge - amzn.to/3mLPfRa
Order My Merch Here - muscle-car-sol...
I'm on Instagram! - / muscle_car_solutions
Wanna buy me a beer? ;) I like beer! / musclecarsolutions
New video cam! - amzn.to/2RkHUJe
Gimbal - amzn.to/2wg8Sbc
My Amazon Store - www.amazon.com...
I’m a novice at this since I’m 70 yrs trying to get back into running wild
Tuning these setups: thank god for the genius quick-change metering rods.
I have set up dual 4's on an open plenum tunnel ram and it worked quite well. I like using progressive linkage for the street. Running on the rear carb primary should act like a 2 barrel carb and as you tip into the secondaries the front carb should be coming in on the primary side to mimic a tri-power carb set up. At full throttle all 8 barrels should be feeding all 8 ports similar to stack injection except that the plenum area is dealing with a intake reversion. I have had good success with this type of set up.
That's the information I was trying to get outta you your a wealth of knowledge, keep the videos coming
I’m glad you found it useful. Thanks for watching! Let me know how yours turns out.
I bought the dual quad Edlebrock vintage series when they first came out. I put this set up on my 454 Chevy in my 1971 LS5 Corvette. I had a professional tune it after I built the motor. It ran 11s on pump gas with a 4speed and 3.90 gears. I had to put an L88 hood on it for clearance. I now have a 2006 Corvette 6speed with a Supercharger. I sold the 71 30 years ago and despite 578 hp at the wheels with current Vette, I miss my 71. At 58 now I’m going to build another big block Chevy with the new RPM dual quad.
Anyone considering this set up , I highly recommend. You can get more top end from a single plane but seat of the pants these win.
Getting a triple setup for my 64 394 Oldsmobile and I'm going to be using three Holly sniper efi units to make tuning easier.
Those things just look cool!
I run a dual carb set up on my 540.
Tried my best to keep it under my hood.
I use an edelbrock intake square port that has been extruded honed to port match. I also use 2 2 inch spacers, with a 3/8 nitrous plate. The intake is also set up with nitrous injectors on each port. My carbs are 850 quick fuel. My timing is set 14 before all in at 38. My carbs are 1 on 1. I street this set up. I also have 3800 converter and Trans brake.
Carbs are 4 idle circuit carbs. My tuning has been between jetting and power valves. O2 sensors on each header port.
Cam is a solid roller.
Yes i street this car.
First off Great video. I'm a retired mechanic and had a guy bring me a 57 chevy with a mild sounding 327 in it. Same set up as your video. The progressive linkage has maybe a eighth inch space before engaging the front carb..he was complaining about pedal pressure and how sudden the rpm hits when shifting his 4 speed..I found the slide on the linkage catching allittle causing high idle when I played arround with weaker springs. Lube didn't help. He's 82 yrs old and wants to grandpaw this thing to th car shows..I drove it and was not impressed with it at all...told him that shit needs work..I suggested because of the way he drives and what he was complaining about to sell that set up at a swap meet and let me put a performer rpm style dual plane with either the 600 or new 650 edelbrock carb on it..well he said I think it looks Cool! Gotta think about it. Lol..my question is should I if I decide to put more time in this widen the engagement to the front carb? It's what I wanted to do but he was ready to go home...we got more important things to fix on this BIRTHDAY CAKE 57 he bought. Thanks for th video..I haven't cked timing or anything else tune related. Told him the way it is now I guarantee I can put a single on it and out perform this and make the drivabuilty much better for pawpaw.
The progressive linkage set up is very simple. Easy to set up, easy to adjust. There was a few years ago one that way way over engineered and cost a fortune ($5-600). Might still be around. Check some of the blower companies and see what they offer. They were butter smooth. It’s been an age since I did any research on that. I always use the Edelbrock kit.
Are you going to have a video on a duel Edelbrock carburetor set up on how the return spring linkage needs to be hooked up I don’t see this in the video and I’m having an issue with my set up trying to find a video that will show how the Spring return is set up for both carburetors.
There are a couple options I’ve seen from Lokar I think. Or I’ve seen single springs placed on each carb but I know some folks are super picky on how things look so not sure if that would be a popular solution.
I am 7 months late commenting but good information! I am planning a 406 small block chevy with a dual quad cross ram. I am working on set up of heads, cam and intake but didn't think about the timing.
Things get more complicated when you add the opportunity for a lot more fuel on an engine that’s not designed to take what the combined carbs are rated at. Thankfully smart solutions have been put in place to work with the situation (linkage) and the normal adjustments only gain importance (tuning, timing). Best of luck on your set up!
Very good video. I've been playing with multiple carburetor systems for many many years and your explanation covers it pretty well. I'm currently setting up another Dual Quad system for a 354 HEMI using a single plane intake and a pair of AVS2s. It will be the first setup I’ve done with the AVSs instead of AFBs. The last dual quads I set up was on another 354 HEMI that was built pretty close to this engine and using the same style/design manifold. It will be interesting to see what if any improvements the AVS2s make over AFBs
I'll just add make sure to pack your patience when you start dialing the system in. Jetting and timing makes a big difference (X2 LOL). Once set up the there is normally very little maintenance required.
My experience is multiple carb systems can be altitude and temperature sensitive. The car can run great one day and like crap the next then good again the following day.......usually due to a large temperature swing, not a mechanical issue with the system. The trick is to find a happy compromise in jetting and timing and do the tuning a day that is "normal" for the area you live/drive in. I live in Arizona at 4500 feet but occasionally make a trip back to Illinois to an altitude of 200 feet. If I'm planning on using the car for those trips, after and I've optimized the car for where I live at I usually set jetting a step or 2 richer than is optimal for the 4500 ft altitude. When I get to an altitude below 1000 ft I normally also retard the timing 2-4 degrees.
I'm one of those old guys who doesn't have an AFR meter, although I have used them in the past (the old style that used a tail pipe sniffer). I have found that an Infrared Thermometer Gun to measure exhaust temperature from the individual cylinders (hotter indicating lean cylinders and cooler a possible rich condition) can be useful to get the initial jetting close. Unfortunately, it's only practical in a stationary situation.
Again you provided some very good information.
I'm dealing with my first dual quad setup , I'm finding the motor likes alot of timing, just wondering if you had any insight on the subject, and maybe what your running. And are you using vacuum advance aswell. Thanks
Building a Nailhead so I’m forced to use these carbs; been Holley since the beginning so thanks for this video, not much on 2 by 4s in avs out there
I’m a little limited with these as I don’t tune many though out the year, and I won’t run one myself. Way too complicated for no return and actually a loss of performance. I just happened to get one back that a customer took off after being constantly frustrated with. Thanks for watching!
That's a very nice setup great video
They are cool looking for sure!
Fantastic video! Just got my set up and will be installing soon. Great info here
Glad it was useful. The tuning process will be a little more complicated but give yourself the opportunity to succeed by making sure the right fuel system set up and you’ve got good command of ignition timing and you’ll do just fine. Best of luck!
Love this vid! Thank you! Subscribed!
Thank you!
Less than two minutes and the good diagram on correct fuel delivery. 👍👍
I have learned how true that is.
Off topic:
When u have time, I lost mech pump. Do u put electric setup, or, back to new mech (and, which one do u need to put extra backup in trunk? Haha!)? Thanks.
Hey man good to see you again! I’m compelled ok with mechanical pumps but o do love the versatility of electric in tank pumps. The GMC got a new mechanical. All situational.
@@MuscleCarSolutions TU!
Are the jets ever close that come with the intake?
Awesome!!!
Thanks!
If you bring the timing up, it increases the idle speed. How do you control that idle speed to bring it down to an acceptable speed. Is the engine running on the back carb. How does the fuel get to the front cylinders.
You dial down the rpm at the carburetor. Additional timing is critical to the tuning success on a two four set up. Yes you run a primary and secondary carburetor. Edelbrock designs intakes to pull fuel and air from both back and front carburetors.
I have an offy dual square bore hi-rise from the mid-'60s and was wondering if my 2 Edelbrock AVS 650 cfm which are square bore would be too much to run on a mild 327ci I would be running a 1 to 1 linkage. Great video thank you, especially the timing part.
If you run a 1 to 1 linkage, yes. It will be way over carbureted.
i put one of these on a new built 468 with brodex heads only been tuning it havnt taken it down the road but i have the front carb as the primary .vac advance is on the front carb and it is set up that both carbs work in tandem and only running a mild flat tappet solid cam with 400 turbo no stall converter .should i just leave it how it is or switch to the rear carb as the primary
Having a 1:1 set up will just set you up for a lot of frustration. Use a progressive kit. Having the back carb your primary is much easier to work with the Edelbrock progressive linkage.
Hi.. ive justbstarted watching your videos.. and well unlikr a lot of folks.. i dont know what my internals are... they look clean.. fresh rebuild.. where mechanic unfortunately lost his lifenin a motorcycle accident.. i bought the motor and then randomly found a edelbrock tunnel ram T5..i beleive.. any eay bbn i have a 318 DEC headers tunnel ram and a choice of dual quats or single ( i have both toppers fpr.the plentom to decide from ... its going in my forst konster truck build.. i live in south Carolin so with noninspection i will be driving her on 44s on the street to the fishing and mud holes round town.. ..
Help.. the smart person in me says do an EFI and be done. The cheap old school says get her two carbs cut the hood and let her eat💁🏾♂️ .. sorry for typos dont have glasses that work.. 😁...
old school it ..I love it .on my 460 dual carb set up .it's badass in my 93 notch ..And Frankenstein my stang is loving it ..wooooo
Another great video!!!
Thanks man! Appreciate that! Hope all has been well with you.
Okay.
First things first.
350/350 4 bolt main crate motor 1972
Dual carbs sitting on top of Elderbrock street tunnel ram. Both carbs are Elderbrock 600 cfm manual choke. Vaccuum secondary.
I looked up the motor spec's and the best I could find is the motor has somewhere around 325 HP
It also has a small street cam with a small loop.
Timing is set @ 12 TDC
Full Timing somewhere in the neighborhood of 30-34
Right now the distributor vaccuum is disconnected.
This motor idles great, cleans out around 2000 RPM.
Here is the deal...if one wanted to take off fast and nail the throttle wide open the motor falls on its face. If I continue to hold the throttle open it will recover after about 4-6 seconds.
Which is horrible 😕
Stock carb came with yellow or orange springs.
I change all 4 springs to which looks like steel.
The only thing it did was make matters worse.
I even tried to advance the Timing a few degrees.
No go.
Oh.. fuel pressure is smack on 6 1/2 psi.
Even W.O.T. it still 6 1/2
Rear spark plugs are a little dark. Front plugs clean.
Th350 trans with shift kit. 373 gears 10 bolt pos.
I would appreciate any help one could offer.
What is your linkage set up? 1:1 or progressive? Cam specs? CR?
When I was a teenager, I didn't care. If the dual quad ran right or not, it looked cool as hell at the Dairy Queen with the hood up.😉
I always thought that you could not over carburate with edelbrocks because the vacuum is what opens the four barrel so it will only pull what it needs...... am I wrong?
One of the worst misconceptions about AVS and weighted air valve secondary carburetors - that the CFM is adjustable because of it. The drop in pressure in the intake under load creates the vacuum that opens the valve and begins metering fuel. But you 1000% can over carburate an engine with an Edelbrock carburetor. See it all day long.
I have a 11.1 327 with street tunnel ram and dual 500 edelbrock carbs I tried progressive linkage and burned up one piston . I'm running 1 to 1 now . You never discuss how to adjust the air-fuel mixture screws I'm old school I use a vacuum gauge for turning , do I need a hat to tune each carburetor separately
Any recommendations on afr set ups? Have two dual quad trucks and hoping this along with your videos will help.
I did a video on the AFR I use but it’s very expensive. I liked the dual O2 option but the wireless is what sold me on it. I can carry my phone under hood and go back and forth to either side and back to the drivers seat while watching the number. Awesome tool. Just pricy.
@@MuscleCarSolutions Thank you I will watch that and shop from there.
Hi id like to ask you a question ive got a 1966 c10 that has a 1972 sbc 350 it , ive been thru lots of intake carbs and finally bought this edelbrock dual quad air gap set from a oldtimmer who raced it. I rebuilt the carbs and when i did the front carb had bigger neddles what size would i need to get them back matched up.
The answer to your question is you have to tune it for your application. There is no magic rod and jet combination that works on everything. I’d put both carbs back to the factory calibration and start tuning from there. That way you’ll know the base calibration and can make your adjustments according to what the engine is asking for. Each carb will get its own combination as they have different jobs to perform.
I know it will never make good power, but for the looks and driveability. Mable two throttle body injectors from the 80's .
You’re better off with the carbs. No way to tune those ancient throttle bodies.
@@MuscleCarSolutions just a thought. If you could use a mega squirt type of control to tune the injectors.
what do you think the proper jet sizes should be on my 2 Rochester carbs that I have on my 454? I have a manifold that demands 1 to 1 linkage. I live in Laurel Mt. with elevation around 2100 feet. Thanks Mo.
Not really an easy answer on that. I’d highly recommend getting an AFR and record every adjustment you make and what the result was. You’re at a low elevation so don’t need to overthink too much on going too lean. Not sure what you mean by the intake demands a 1:1 linkage. Is this a cross ram?
Poly 318 1966 Mopar,when talking timing, it’s all before top dead center correct?
Yes that’s correct.
Where can I purchase dual quad linkage that you are showing, I have a 66 charger 318 poly dual quad setup that I would like to finish Thanks
Edelbrock sells it on their website.
You can run 2x 850s also. The reason is the Venturi vacuum signal is half that it would be in a single 4 bbl carb. The smaller 2x 4 carbs are more sensitive and can work exceptionally well but counter intuitively the carbs that are too big when dialed in can work really well also and tend to produce more power up top closer to say what a well set up single 4bbl would.
In other words there is more than one way to skin a cat. 2x small 4bbls or 2x large ones.
The trouble is exactly what you mentioned. When there isn’t enough air speed and pressure drop below the booster, it doesn’t meter fuel through the main metering circuit properly. So folks over compensate with a bigger jet to try and add more fuel. It’s a snowball effect. If you monitor the activity with an AFR, you’ll see the negative effects immediately.
I have a 66 Impala 4sp 327. I kinda inherited my buddies old corvette duel quad intake. The car is bone stock with duel exhaust. Will dual 500 cfm AVS carbs work on this application or would that over fuel the motor? Thank you Sir. Rick
Hard to say without knowing what the 327 is. Cam, compression, cylinder heads. Likely that set up could be on the rich side because of the small cubic inches, but the other factors could help balance that out depending on what’s been done to the engine.
HE'll yes go for it
Great video thanks for sharing your knowledge and attention to detail! I’m building a 428cj (434ci)😊10.4:1 compression, 227/237 114LSA at 630 gross lift. Completely rebuilt, trick flow heads, a blue thunder med riser dual quad intake. I’ve been looking at dual AVS 500s or 650s with the intention of a mostly street occasionally strip type build. What are your thoughts. I saw another post where you suggested you weren’t a fan of the AVS so I’m curious on your overall thoughts and recommendations on an ideal 2x4 setup for this given my intention.
I’ve never said I wasn’t a fan of the AVS. The exact opposite! Now dual quad or tunnel rams is another story. 😂 I’d use 500s if that were my build.
Hahah, ok fantastic thank you
So progressive is the best for my application?
I don’t know what your application is?
I have a marine Chevy small block 383. It has old school forged TRW pistons. 9.6:1 static, 8.65:1 dynamic compression is planned when it goes back together. It's apart for decking and a hone and I haven't checked final compression height yet.
It has a Comp CS268XFI HR13 cam. Which is 268/276 duration, 218/224 @50. So not crazy, but marine needs dependability. It also has a Holley marine electric fuel pump wired to the oil pressure system for safety, it has a return style regulated 3/8 ID fuel delivery system with 2 filters.
I'm looking into an Edelbrock dual 500 setup for it. I have a marine Weber from before, so I can tune an Edelbrock. As I imagine you know, they are effectively the same stuff.
Do you think that the dual 500's would be overdoing things for this 383?
BTW I have an AFR display and a dash mount vacuum gauge. They have been a huge help.
I'd be replacing a 4 barrel Quickfuel 750.
Yes it usually is, which is my the progressive linkage set up is so important.
I am running a 355 Chevy TRW flattops ported 441 heads with the old comp 268 cam with 1.6 comp rockers. 2:38 gears with a 2800 stall. Edelbrock air gap with 2 500 AVS. Progress linkage Afr gauge.
Runs spot on at idle and cruise. 14-1 idle and high 13-1 cruise. When I go to WOT it instantly drops to 11-1 and with in a few seconds it keep dropping and craps out 9-1. Any ideas on where to start? Fuel pressure at 4.5 and timing is all in at 36. Ran great with a Holley double pumper. Thanks Jim
What have you done to adjust the carbs?
@@MuscleCarSolutions the only thing was springs in the primary carb. My second kit showed up from Summit yesterday.
Time to start tuning!
Well I guess fat rods are the easiest.
@@SixDegreesofJim no. Following the tuning chart is the easiest. If you just start randomly changing rods or jets, it’s going to take you longer to dial it in. Follow the chart. It’s there to take the guesswork out of it.
I have a 454 with a 620 lift roller cam and a rpm air gap with avs2 800 could i get a tunnelram and just buy another carb to match would it run and drive nice ?
I’m afraid you’ll never be able to tune that so it’s not extremely rich. The 800 demands a decent amount of airflow to meter fuel properly. Tunnel rams suck unless in their designed state of WOT. With that unknown cam (lift doesn’t mean anything, duration snd LSA is far more important to know in this situation) and your desire for a cruiser, two 500s, progressive linkage, two calibration kits and an AFR would help you make it drivable.
Strange I see guys running a 440 with 2 avs2 800 carbs and they say runs great on a 1 to 1 linkage I hate this so many different options idk what to do lol I here not to run progressive with tunnel ram and herd 500s are way to small for my combo 😂..... I guess efi is the easy way no he said she said bs just turn the key and it's perfect 😂but so expensive...... I have edelbrock 2261 cam I have domed pistons I'm at least 9.5.1 runs 12.5 in 1/4 mile idk I wish some one can help me.......
@@jesseparadis6141 put two 800s on and a 1:1 linkage with an AFR and you’ll figure it out pretty quickly. People tend to just put up with bad carburetor tuning just because it starts and drives. But it’s at 12:1 at idle and cruises around fatter than that and an oil fan full of gas soaked oil. So much better when they’re actually tuned right.
Oh ok sound good
Is the rear carb always the primary?
Generally, yes.
What better for this setup, AFB or AVS?
Pick one. The AVS2 however is much better.
Carburetors will outrun fuel injection systems my friend. 😡🚘
That’s a situational statement. They have the possibility to in some instances. For example. If I had the choice between a modern port injection EFI over a dual quad set up for a cruiser, I’d choose the EFI all day long. Simply out of the amount of endless fiddling that a two four set up requires. It’s all in what you’re willing to put up with.
I can't watch the video because the hand drives me nuts
Your loss!
First of all I run a weind model number 1985 tunnel ram, your information has no effect on that manifold, how about trying one of those sometimes ,there is no fuel crossover from front carb to back carb, progressive linkage useless, on a performance engine all we care about is Total advance, we don't drive our cars around at idle so why even bring it up.
You drive at WOT everywhere you go? Cool! 😆😆
I watch alot of your vids love them, Thanks! Just curious i cant figure out why i have a very SHARP exhaust smell when i park shut off. I know the regular smell of fuel. I have 350/265 new crate motor 10 degrees inital 32 total eddy carb 600 cfm New .. I just seems odd i mean its peircing smell. Any Ideas? fuel pressure 5 psi with regulator. Thanks Sir..
Hard to say. I’ve had that before with bad fuel. If you’re running something that’s got 10% ethanol (or more), it’s really good at picking up contaminants that can change the smell of the fuel and exhaust. How long has it been occurring? On the current tank of fuel or for an extended period of time?
@@MuscleCarSolutions Just recently mobile gas 87 octane.
Maybe i should do shell gas,, 91 octane?
@@lordsauto I’d switch brands for a tank or two. Hard to say what it picked up but it’s not uncommon to occasionally get a different smelling fuel/exhaust.
@@MuscleCarSolutions ok will give it a try thanks for the quick reply..